Revert of Disabled memory.mobile_memory

tools/perf/benchmarks/memory.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from core import perf_benchmark
 
 from measurements import memory
 import page_sets
 from telemetry import benchmark
 
 
-@benchmark.Disabled('all')
+@benchmark.Enabled('android')
 class MemoryMobile(perf_benchmark.PerfBenchmark):
   test = memory.Memory
   page_set = page_sets.MobileMemoryPageSet
 
   @classmethod
   def Name(cls):
     return 'memory.mobile_memory'
 
 
 # Disable on yosemite due to crbug.com/517806
 # Disable on reference due to crbug.com/539728
 # Disable on all Mac as it's also failing on 10.11 and retina.
 # crbug.com/555045
 @benchmark.Disabled('mac', 'reference')
 class MemoryTop7Stress(perf_benchmark.PerfBenchmark):
   """Use (recorded) real world web sites and measure memory consumption."""
   test = memory.Memory
   page_set = page_sets.Top7StressPageSet
 
   @classmethod
   def Name(cls):
     return 'memory.top_7_stress'
 
   @classmethod
   def ShouldDisable(cls, possible_browser):
     return cls.IsSvelte(possible_browser)  # http://crbug.com/555092